US manufacturers have urged a US trade delegation set to visit China to demand that the Asian giant open its markets and reform its currency.

The National Association of Manufacturers (NAM) stated its concerns at a meeting with US Treasury Secretary Henry Paulson and other officials.

"We need to see progress with China and we need to see it soon," said the trade group's president John Engler.

US officials will be going to Beijing next week to discuss trade.

The visit comes ahead of data that is expected to show that the US trade deficit with China has expanded beyond last year's $202bn (£102bn).

Mr Paulson, who will be travelling with US Trade Representative Susan Schwab and Commerce Secretary Carlos Gutierrez, is the third US Treasury Secretary to take up the issue of China's currency and its markets.

"They were all pretty upbeat about the possibilities and felt this was a good time to engage China," said Pat Mears, NAM's director for international commercial affairs.

Many in the US have accused China of maintaining its currency artificially weak in order to boost exports.

Some say China's currency, the yuan, is undervalued by between 15-40% in relation to the dollar.